How can I set the NaN values to black in a pcolor plot?

Hi all!

Is there any way to set the NaN values as black/grey or any other color instead of white?

I am using this code but it's not working.

% Generate sample data
data = rand(10, 10);
data(3, 3) = NaN;  % Set a specific value as NaN

% Create the pcolor plot
figure;
pcolor(data);
shading interp;
colorbar;

% Set NaN values to black
colormap(gca, 'jet');
colormap(gca, 'parula'); % or any other colormap you prefer
c = colorbar;
c.Label.String = 'Temperature';

% Set NaN values to black
colormap(gca, 'parula');
caxis([nanmin(data(:)), nanmax(data(:))]);
cmap = colormap;
cmap(1, :) = [0 0 0];  % Set the first row of colormap to black
colormap(gca, cmap);

% Add colorbar labels and title
xlabel('X-axis');
ylabel('Y-axis');
title('pcolor Plot with NaN Values Set to Black');

any feedback will be much appreciated!!

Answer 1

[the cyclist]

Set the axes background color to black:

% Generate sample data
data = rand(10, 10);
data(3, 3) = NaN;  % Set a specific value as NaN

% Create the pcolor plot
figure;
pcolor(data);
shading interp;
colorbar;

% Set axis background color to black, so it "shows through" at the missing
% values
set(gca,'Color','black')

% Add colorbar labels and title
xlabel('X-axis');
ylabel('Y-axis');
title('pcolor Plot with NaN Values Set to Black');

Answer 2

[VBBV]

% Generate sample data
data = rand(10, 10);
data(3, 3) = NaN; % Set a specific value as NaN

% Create the pcolor plot
figure;
h = pcolor(data);
h.CData(2:4,2:4) = 0;
shading interp;
colorbar;

% Set NaN values to black
c = colorbar;
c.Label.String = 'Temperature';
% 
% % Set NaN values to black
colormap(gca, 'parula');
caxis([nanmin(data(:)), nanmax(data(:))]);
cmap = colormap;
cmap(1, :) = [0 0 0];  % Set the first row of colormap to black
colormap(gca, cmap);

% Add colorbar labels and title
xlabel('X-axis');
ylabel('Y-axis');
title('pcolor Plot with NaN Values Set to Black');

[VBBV]

One way is you can set the colordata vlaues to 0

h.CData(2:4,2:4) = 0;